Wyss responsive post images

wyss_responsive_post_images.php

function wyss_responsive_post_images( $content ){
  // unwrap images of links, except the one in the video embed
  $content = preg_replace('/(?<!\<\/iframe>)<a.*?>(<img.*?>)<\/a>/', '$1', $content);
  // wrap imgs in figures (if not in figures)
  $content = preg_replace('/(\s|^)(<img.*?( class=[\'\"].*?[\"\']).*?>)(\s|$)/', '<figure$3>$2</figure>', $content);
  // remove style from figure
  $content = preg_replace('/(figure[^>]*) style=(\"|\')+[a-zA-Z0-9:;\.\s\(\)\-\,\#\_]*(\"|\')/', '$1', $content);
  // remove ID from figures
  $content = preg_replace('/(figure[^>]*) id=(\"|\')+[a-zA-Z0-9:;\.\s\(\)\-\,\#\_]*(\"|\')/', '$1', $content);
  // unwrap <div class="entry-content-asset">
  $content = preg_replace('/<div class=(?:\"|\')entry-content-asset(?:\"|\')>\n<figure>([\S\s]+?)<\/figure>\n<\/div>/', '<figure>$1</figure>', $content);

  if ( ! preg_match_all( '/(<figure [^>]+>)(<img [^>]+>)/', $content, $matches ) ) {
    return $content;
  }

  $selected_images = $attachment_ids = array();
  $figures = array();

  foreach( $matches[1] as $figure ) {
    array_push($figures,$figure);
  }

  foreach( $matches[2] as $image ) {
    if ( false === strpos( $image, ' srcset=' ) && preg_match( '/wp-image-([0-9]+)/i', $image, $class_id ) &&
        ( $attachment_id = absint( $class_id[1] ) ) ) {

      /*
       * If exactly the same image tag is used more than once, overwrite it.
       * All identical tags will be replaced later with 'str_replace()'.
       */
      $selected_images[ $image ] = $attachment_id;
      // Overwrite the ID when the same image is included more than once.
      $attachment_ids[ $attachment_id ] = true;
    }
  }

  if ( count( $attachment_ids ) > 1 ) {
    /*
     * Warm object cache for use with 'get_post_meta()'.
     *
     * To avoid making a database call for each image, a single query
     * warms the object cache with the meta information for all images.
     */
    update_meta_cache( 'post', array_keys( $attachment_ids ) );
  }

  $index = 0;
  foreach ( $selected_images as $image => $attachment_id ) {
    $image_meta = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
    $img_options = array();
    $figure_align = "alignnone";

    if(preg_match('/(align.*?)(?:\s|")/', $figures[$index], $align)) {
      $figure_align = trim($align[1]);
    }

    switch ($figure_align){
      case 'alignleft':
        $img_options = array(
          'w' => $image_meta['width'],
          'h' => $image_meta['height'],
          'sizes' => array(
            array(
              'media' => 'xlarge+',
              'w' => '467px'
            ),
            array(
              'media' => 'xlarge',
              'w' => 'calc( (100vw - 160px) / 3 )'
            ),
            array(
              'media' => 'large',
              'w' => 'calc( (100vw - 120px) / 3 )'
            ),
            array(
              'media' => 'medium',
              'w' => 'calc( (100vw - 120px) / 3 )'
            ),
            array(
              'media' => 'xsmall',
              'w' => 'calc(100vw - 40px)'
            ),
          ),
          'srcset' => array(2000,1600,1200,800,400)
        );
        break;
      case 'alignright':
        $img_options = array(
          'w' => $image_meta['width'],
          'h' => $image_meta['height'],
          'sizes' => array(
            array(
              'media' => 'xlarge+',
              'w' => '690px'
            ),
            array(
              'media' => 'xlarge',
              'w' => 'calc( (100vw - 120px) / 2 )'
            ),
            array(
              'media' => 'large',
              'w' => 'calc( (100vw - 90px) / 2 )'
            ),
            array(
              'media' => 'medium',
              'w' => 'calc( (100vw - 90px) / 2 )'
            ),
            array(
              'media' => 'xsmall',
              'w' => 'calc(100vw - 40px)'
            ),
          ),
          'srcset' => array(2000,1600,1200,800,400)
        );
        break;
      default:
        $img_options = array(
          'w' => $image_meta['width'],
          'h' => $image_meta['height'],
          'sizes' => array(
            array(
              'media' => 'xlarge+',
              'w' => '1177px'
            ),
            array(
              'media' => 'xlarge',
              'w' => 'calc( ((( (100vw - 80px) - (11 * 40px)) / 12) * 10) + 360px )'
            ),
            array(
              'media' => 'large',
              'w' => 'calc( ((( (100vw - 60px) - (11 * 30px)) / 12) * 11) + 300px )'
            ),
            array(
              'media' => 'medium',
              'w' => 'calc(100vw - 60px)'
            ),
            array(
              'media' => 'xsmall',
              'w' => 'calc(100vw - 40px)'
            ),
          ),
          'srcset' => array(2000,1600,1200,800,400)
        );
        break;
    }

    $generated_img = wyss_get_image_tag($attachment_id, $img_options);
    $content = str_replace( $image, $generated_img, $content );
    $index++;
  }
  return $content;
}
add_filter( 'the_content', 'wyss_responsive_post_images', 99 );